blackout curtain; light-blocking curtain; lampshade; shade
A curtain or shade that blocks light. Often used in contexts like photography darkrooms, bedrooms, or lamps. The cross-reference 遮光カーテン is a more common term for blackout curtains.
See also: 遮光カーテン
A blackout curtain is necessary in a photo developing room.
When you close the light-blocking curtain, the room becomes pitch dark.
Compound of 遮光 (light-blocking) and 幕 (curtain, screen). The exact historical derivation is uncertain, but the word is formed from standard Sino-Japanese elements.